CARBONIFEROUS PERIOD
Terrestrial life was well established by the Carboniferous
period. Amphibians were the dominant land vertebrates, of which one branch
would eventually evolve into reptiles, the first fully terrestrial vertebrates.
Arthropods were also very common, and many (such as Meganeura), were much
larger than those of today. Vast swaths of forest covered the land, which would
eventually be laid down and become the coal beds characteristic of the
Carboniferous system. A minor marine and terrestrial extinction event occurred
in the middle of the period, caused by a change in climate. The latter half of
the period experienced glaciations, low sea level, and mountain building as the
continents collided to form Pangaea.
Early Carboniferous land plants, some of which were
preserved in coal balls, were very similar to those of the preceding Late
Devonian, but new groups also appeared at this time.
The main Early Carboniferous plants were the Equisetales
(horse-tails), Sphenophyllales (vine-like plants), Lycopodiales (club mosses),
Lepidodendrales (scale trees), Filicales (ferns), Medullosales (informally
included in the "seed ferns", an artificial assemblage of a number of
early gymnosperm groups) and the Cordaitales. These continued to dominate
throughout the period, but during late Carboniferous, several other groups,
Cycadophyta (cycads), the Callistophytales (another group of "seed
ferns"), and the Voltziales (related to and sometimes included under the
conifers), appeared.
The Carboniferous lycophytes of the order Lepidodendrales,
which are cousins (but not ancestors) of the tiny club-moss of today, were huge
trees with trunks 30 meters high and up to 1.5 meters in diameter. These
included Lepidodendron (with its fruit cone called Lepidostrobus), Halonia,
Lepidophloios and Sigillaria. The roots of several of these forms are known as
Stigmaria. Unlike present day trees, their secondary growth took place in the
cortex, which also provided stability, instead of the xylem. The Cladoxylopsids
were large trees, that were ancestors of ferns, first arising in the
Carboniferous.
The fronds of some Carboniferous ferns are almost identical
with those of living species. Probably many species were epiphytic. Fossil
ferns and "seed ferns" include Pecopteris, Cyclopteris, Neuropteris,
Alethopteris, and Sphenopteris; Megaphyton and Caulopteris were tree ferns.
The Equisetales included the common giant form Calamites,
with a trunk diameter of 30 to 60 cm (24 in) and a height of up to 20 m (66
ft). Sphenophyllum was a slender climbing plant with whorls of leaves, which
was probably related both to the calamites and the lycopods.
Cordaites, a tall plant (6 to over 30 meters) with
strap-like leaves, was related to the cycads and conifers; the catkin-like
inflorescence, which bore yew-like berries, is called Cardiocarpus. These
plants were thought to live in swamps and mangroves. True coniferous trees
(Walchia, of the order Voltziales) appear later in the Carboniferous, and
preferred higher drier ground.
SUPPLEMENT FROM THE ENCYCLOPEDIA BRITANNICA
PUBLISHED 1824
Calamites 'Horsetail'
PUBLISHED 1824
Calamites 'Horsetail'
Calamites is a genus of extinct arborescent (tree-like)
horsetails to which the modern horsetails (genus Equisetum) are closely
related. Unlike their herbaceous modern cousins, these plants were medium-sized
trees, growing to heights of more than 30 meters (100 feet). They were
components of the understories of coal swamps of the Carboniferous Period
(around 360 to 300 million years ago).
Cordaites Tree
Cordaites is an important genus of extinct gymnosperms which
grew on wet ground similar to the Everglades in Florida. Brackish water mussels
and crustacea are found frequently between the roots of these trees. The
fossils are found in rock sections from the Upper Carboniferous (323 to 299
million years ago) of the Dutch - Belgian - German coal area. A number of many
noteworthy types from this line are:
In 1997 a fossil tree was found in an open-cast coal mine at
Great Lumley. Parts of this "Cordaites" tree are on display in the
Durham Botanic Gardens and at Great Lumley Millennium Park
These fossil trees have been examined by Professor Andrew
Scott of London University, who reports that they are examples of an ancestor
of modern fir trees (conifers). Logs of this type with similar carbonate
mineralisation, have been found elsewhere in the world, but not previously in
Britain. They are called Cordaites, a name used for extinct seed-bearing plants
related to the conifers, Cordaites was a tall tree, up to 30 meters high, that
had narrow strap-like leaves about one meter long. Although the long stems have
not previously been found in Britain, leaves and branches are common fossils in
the Coal Measures. The occurrence of mineralised tree trunks at Priors Close
and not at other Coal Measures in Britain needs explanation.
Durham Botanic Gardens
Great Lumley Millennium Park
Cordaites Tree - Leafs #1 [Nose Point, Seaham, Co. Durham]
Cordaites Tree - Leaf Close Up #1 [Nose Point, Seaham, Co. Durham]
Sigillaria Tree
Stigmaria: This fossil tree is one of the earliest trees, a
Sigillaria, from the carboniferous period 320 million years ago.
Sigillaria tree from Stanhope, County Durham, UK
The tree was found in a stone quarry near Edmundbyers Cross
in 1915 and brought to the churchyard, where it is a prominent feature of the
town centre.
Lonchopteris
Lonchopteris eschweileriana
Specimen: [Rare]
Lonchopteris eschweileriana
Locality: Poland, GZW - Upper Silesia Coal Basin
Stratigraphy: Westfal
B - "Orzeskie" Beds
Age: circa 305 million years
Dimensions: 9, 0 x 4, 0 x 0, 5 cm [fern 6, 0 cm long]
Seed ferns (Pteridosperms) like Lonchopteris were group of
seed plants from the Carboniferous and Permian periods (about 360 to 250
million years ago). Some, such as Medullosa ( Lonchopteris, Neuropteris,
Alethopteris etc.) grew as upright, unbranched woody trunks topped with a crown
of large fernlike fronds; others, such as Mariopterids, were woody vines.
All had fernlike foliage; however, they reproduced by seeds,
with ovules and pollen organs attached to the fronds. Gamete - producing
structures in the seeds were surrounded by a hard inner integument and a fleshy
outer layer. These features have led some authorities to speculate that these
seeds may have been dispersed by animals. Some seeds were large. ( Pachytesta
gigantea, a seed of Medullosa, grew up to 7 cm long.) Pollen organs of seed
ferns were also large and complex and were commonly made up of many pollen sacs
fused into a large structure.
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